For doing POC and testing sometimes we need multiple Virtual Machines very quickly. So here in this post we will create multiple virtual machine with one Vagrantfile by using Vagrant. We will cover some examples from coding side in Vagrantfile, it will help you in your real time scenarios as well.

As we know Vagrant is written in Ruby language, so we will use some Ruby code in Vagrantfile.
We use the Multi VMs for various technology POC like system Cluster,High Availability, automation tool (like chef,puupet and ansible) etc. etc.

Example 1: With basic Vagrantfile
Example 2: Using loop in Vagrantfile
Example 2: Nested loop-conditional statement in Vagrantfile

Syntax:
Block_Name.vm.define : To define the new VM, use this code. You will see more examples and will understand how to define this.

Create Multi VM With basic Vagrantfile

In this scenario,we will create three VM from single Vagrantfile. We will create VMs for Web Server, MySQL Server and FTP server. It will just create the 3 Virtual Machines with different Operating System.

mkdir -p ~/vagrant_box/example1 && cd ~/vagrant_box/example1 

# create file
vi Vagrantfile

#paste the given below content in Vagrantfile
Vagrant.configure("2") do |config|
  #config.vm.box = "base"

  config.vm.define "web" do |web|
    web.vm.provider "virtualbox" do |vb_web|
      vb_web.memory = 1024
      vb_web.cpus = 2
    end

    web.vm.box = "centos/8"
    web.vm.hostname = "web01"
    web.vm.network "private_network", ip: "192.168.33.10"

  end

  config.vm.define "mysql" do |mysql|
    mysql.vm.box = "debian/buster64"
    mysql.vm.hostname = "mysql01"
    mysql.vm.network "private_network", ip: "192.168.33.11"

  end

  config.vm.define "ftp" do |ftp|
    ftp.vm.box = "freebsd/FreeBSD-12.1-STABLE"
    ftp.vm.hostname = "ftp01"
    ftp.vm.network "private_network", ip: "192.168.33.12"
  end

end

# now create multi VM
vagrant up

Create Multi VM using loop in Vagrantfile

Here, also we will create 3 Virtual Machines. We have defined the array vm_name and then used the ruby loop to create all these 3 Virtual Machines. One thing to notice that all these VMs will have same Operating System.

mkdir -p ~/vagrant_box/example2 && cd ~/vagrant_box/example2 

# create file
vi Vagrantfile

Vagrant.configure("2") do |config|
  vm_name=['web01','mysql01','ftp01']
  vm_name.each do |i|
      config.vm.define "#{i}" do |node|
      node.vm.box = "centos/8"
    end
  end
end

# now create multi VM
vagrant up

This is another example of loop but here the VM name will be like node-1, node-2 and node-3 .

mkdir -p ~/vagrant_box/example3 && cd ~/vagrant_box/example3 

# create file
vi Vagrantfile

(1..3).each do |i|
  config.vm.define "node-#{i}" do |node|
    node.vm.box = "centos/8"
  end
end

# now create multi VM
vagrant up

Create Multi VM using nested loop and conditional statement in Vagrantfile

Because we can use ruby code in Vagrant, we add some Nested loop and condition in this example.
Here, if vm_name is ftp01 OR web01 it will create Virtual Machine with CentOS 8 operating system else create Virtual Machine with CentOS 7 Operating System.

mkdir -p ~/vagrant_box/example4 && cd ~/vagrant_box/example4 

# create file
vi Vagrantfile

Vagrant.configure("2") do |config|
  vm_name=['web01','mysql01','ftp01']
  vm_name.each do |i|
    if "#{i}" == 'ftp01' OR "#{i}" == 'web01' then
      config.vm.define "#{i}" do |node|
        node.vm.box = "centos/8"
      end
    else
      config.vm.define "#{i}" do |node|
        node.vm.box = "centos/7"
      end
    end
  end
end

# now create multi VM
vagrant up